Some of the frogs in this area are particularly notable for their coloring. Two are almost solid gold in color. Perhaps the most notable is Brachycephalus ephippium, which not only is brilliant gold in hue but has armor plates of bone on back and head, and whose tadpoles are nearly three times the size of the adults. All the adults, less than an inch long, have the armor plate strongly developed, although the shape and size shows considerable variation. The general form of the bony deposition just under the skin, in no way connected with the skeleton, appears to be typically that of an hour glass across the back with one or more separate bony islands. Sometimes these islands are fused with the hour glass. The adults hide under leaves and fallen tree trunks in high mountain woodlands and come out in large numbers only in rainy weather. They appear to be rather clumsy creatures. Their gait is a slow walk. The nightly chorus of certain of the frogs sounds like a regiment beating on tin pans. Others have calls that are like the sounds made by winding a watch or filing iron. The “tin-pan frog” is one of the most conspicuous creatures of the region. The chorus of singing males gives a booming metallic sound which seems at times to be a regular clanging, like that of a blacksmith hammering on an anvil. The “tin-pan” frog builds its own house—a crater-like structure of mud projecting above shallow water within which its eggs are laid during the dry season. These nests usually are constructed close to the water’s edge. Here the eggs hatch and the young tadpoles are swept into the pond by the next heavy rain. The mud walls apparently protect the eggs from depredations by fish. Adults stay in trees except at the time of egg-laying. The male is said to come to the pond first to build the nest, before the female arrives to lay the eggs. The frog that quacks like a duck is a closely related species. It has a peculiar habit of swarming. Hundreds may appear at one time in a single tree. One of the golden frogs is about three inches long and almost pure gold in color. Its voice is like the slow grunting of a pig. It sleeps during the day in large leaves of bromeliads, trees of the pineapple family that often hold rainwater in their axils. They sometimes are described as living “tubs of water.” At night the frogs come down out of the leaves and go to ponds and streams in the neighborhood in search of insects. Their leaf sleeping chambers apparently give them complete protection from their natural enemies. One gray and brown Brazilian frog, extremely sluggish by day, when handled assumes a wooden, dead appearance, with the limbs brought close to the body and the head bent forward, so that it resembles a patch of fungus or a chip of wood. Even when left on their backs for a long time they continue to play dead.